SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '498d62381f4eb1cae494c5bb41382713f751fa1f46813347e01fe9551fd69fd8' 
  AND token = 'ibejVamunrB6ZWCA+Rt8IKaSLVSs5i/ZDNzeht8JVPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}